1. Field of the Invention
This invention generally relates to a channel assigning system for use in an electronic musical instrument, and more particularly, to an improved system for deciding a priority for assigning a channel to a musical tone.
2. Description of the Related Art
A process (hereunder referred to as a first conventional process) of assigning a musical tone generating channel (hereunder sometimes referred to simply as a channel) to a musical tone to be effected by a conventional channel assigning system for use in an electronic musical instrument will be first described hereinbelow. For example, in the case of an electronic keyboard instrument, when all channels are in an ON state and a key of the electronic keyboard instrument is pressed down, a channel is assigned to a musical tone corresponding to the pressed key in the following manner.
First, the current loudness levels of envelopes of musical tones corresponding to channels are compared, in a search for a channel corresponding to a musical tone having an envelope which has the smallest current loudness level, and the channel discovered by the search to correspond to a musical tone having an envelope which has the smallest current loudness level, is assigned to a musical tone corresponding to the pressed key.
Further, another process of assigning a channel to a musical tone (hereunder referred to as a second conventional process) is employed in the conventional channel assigning system. In the second conventional process, weighting factor data representing a priority for assigning a channel to a musical tone corresponding to each key is prestored in the system, and further, weighting factor data corresponding to the pressed key is read out simultaneously with the assignment of a channel to a musical tone corresponding to the pressed key, and is stored as data corresponding to the assigned channel. Then, a value indicated by the weighting factor data corresponding to the assigned channel is reduced with time, and accordingly, when a key is newly pressed down, a channel corresponding to weighting factor data having the smallest value is assigned to a musical tone corresponding to the newly pressed key.
Problems arise with the above described processes, however, when the electronic musical instrument is played. For example, where a melody is performed by quickly and successively operating keys in a high frequency range while an accompaniment chord is being played on keys in a low frequency range and a damper pedal is used, the accompaniment chord composed of musical tones in the low frequency range is drowned out by musical tones in the high frequency range corresponding to the melody. This is annoying to the listeners, and further, prevents the player from showing a proper level of skill when performing a piece of music.
Note, the second conventional process can alleviate the above problem to some extent by extending the sounding of the chord composed of musical tones in the low frequency range for a slightly longer time, in comparison with the first conventional process, but cannot completely eliminate the problem.
The present invention has been created to solve the problems of the conventional systems.
Accordingly, an object of the present invention is to provide a channel assigning system for use in an electronic musical instrument in which, while musical tones in a certain frequency range are being quickly performed, a radiation of musical tones in another frequency range corresponding to keys which are pressed is not stopped, whereby a natural and skilled performance can be achieved.